Technical data

96 U1401A User’s and Service Guide
5 Application Examples
Diode Test
A good diode allows current to flow in one direction only.
To test a diode, turn the circuit power off, remove the diode
from the circuit, and proceed as follows:
1 Turn the rotary switch to the / position.
2 Connect the red and black probe leads to the positive and
negative input terminals respectively.
3 Probe the positive (anode) side of the diode with the red
lead, and the negative (cathode) side with the black lead.
4 Reverse the probe leads and measure the voltage across
the diode again.
5 If the diode is:
• Good: In step 3, a forward voltage drop typically from
0.3 V to 0.8 V is indicated (the instrument can display
diode voltage drops up to approximately 2.1 V)
accompanied by a beep. In step 4, OL is indicated.
• Shorted: A voltage drop of nearly 0 V is indicated in
both directions, and the instrument will beep
continuously.
• Open: OL is indicated in both directions.
NOTE
The cathode of a diode is the side indicated with band(s).